Molybdenum silicide / silicon nitride composite infrared emitter apparatus and method of use thereof

Abstract

The invention comprises an infrared source and method of use thereof comprising the steps of: (1) providing a solid state source, comprising an electrically conductive layer of a composition of molybdenum silicide and silicon nitride; (2) providing a heating element embedded in the solid state source; (3) applying an alternating/pulsed current to the heating element to heat the heating element; and (4) heating the electrically conductive layer of molybdenum silicide silicon nitride to at least seven hundred degrees using thermal conduction from the heating element resultant in the electrically conductive layer emitting infrared light in a range of 1.1 to 20 micrometers, where the infrared source operates continuously with heating and cooling of the molybdenum silicide silicon nitride through a differential of at least 200° C. occurring at least five and less than thirty times per second.

1 . A method for generating infrared light comprising the steps of:
 providing a solid state source, comprising:
 an electrically conductive layer comprising at least ninety percent: (1) molybdenum silicide and (2) silicon nitride; 
 a heating element embedded in said solid state source; 
   applying a pulsed current to said heating element to heat said heating element;   heating said electrically conductive layer to at least seven hundred degrees using thermal conduction from said heating element; and   said electrically conductive layer emitting the infrared light, the infrared light comprising photons in the range of 1.1 to 20 micrometers.   
     
     
         2 . The method of  claim 1 , said step of heating further comprising the step of:
 thermally conducting heat from said heating element through an intervening layer to said electrically conductive layer.   
     
     
         3 . The method of  claim 2 , further comprising the step of:
 protecting an emission side surface of said electrically conductive layer from oxidation using a first layer comprising at least one of silicon nitride and silicon oxide.   
     
     
         4 . The method of  claim 2 , further comprising the step of:
 heating said heating element to at least seven hundred degrees centigrade and cooling said heating element to under two hundred degrees centigrade at least five times per second and less than thirty times per second over a time period of at least a minute.   
     
     
         5 . The method of  claim 4 , said step of emitting further comprising the step of:
 generating a distribution of photon energies with a peak intensity in a range of 1.5 to 6.0 micrometers, wherein said electrically conductive layer comprises MoSi 2  and SiN x , wherein 0.5<x<1.5.   
     
     
         6 . The method of  claim 5 , said step of emitting further comprising:
 generating a distribution of photon energies with a peak intensity in a range of 3.0 to 10.0 micrometers, wherein said electrically conductive layer comprises 4 MoSi 2 +SiN x  with a purity of at least ninety percent.   
     
     
         7 . The method of  claim 4 , said step of emitting further comprising:
 generating a distribution of photon energies with a peak intensity in a range of 3.9 to 10.0 micrometers, wherein said electrically conductive layer comprises 4 MoSi 2 +Si 3 N 4 .   
     
     
         8 . The method of  claim 7 , further comprising the step of:
 transmitting a portion of the infrared light through at least eighty percent of a thickness of said electrically conductive layer.   
     
     
         9 . The method of  claim 7 , said step of emitting further comprising the step of:
 emitting photons from an internal volume of said electrically conductive layer; and   transmitting at least fifty percent of the photons to an outer surface of said electrically conductive layer.   
     
     
         10 . The method of  claim 1 , said step of applying a pulsed current to said heating element further comprising the step of:
 isolating the current to said heating element through use of: a first deposited dielectric film on a first side of said heating element and a second deposited dielectric film on a second side of said heating element.   
     
     
         11 . An apparatus for providing infrared light, comprising:
 a solid state source, comprising:
 an electrically conductive layer comprising a composite of at least fifty percent: (1) molybdenum silicide and (2) silicon nitride; 
   a heating element embedded in said solid state source, wherein, during use, heat from said heating element heats said electrically conductive layer to at least seven hundred degrees via thermal conduction, resultant in the composite of molybdenum silicide and silicon nitride emitting the infrared light, the infrared light comprising photons in the range of 0.7 to 20 micrometers.   
     
     
         12 . The apparatus of  claim 11 , said heating element further comprising:
 a connection for connecting to an duty cycle driver, wherein the pulsed current heats said heating element during use.   
     
     
         13 . The apparatus of  claim 12 , said composite of molybdenum silicide and silicon nitride, comprising:
 MoSi 2 ; and   SiN x , 0.5<x<1.5.   
     
     
         13 . The apparatus of  claim 12 , said composite of molybdenum silicide and silicon nitride, comprising at least ninety percent:
   4MoSi 2 +SiN x , 0.5 <x< 1.5.   
     
     
         13 . The apparatus of  claim 12 , said composite of molybdenum silicide and silicon nitride comprising less than ten percent carbon. 
     
     
         14 . The apparatus of  claim 12 , said composite of molybdenum silicide and silicon nitride comprising less than one percent carbon. 
     
     
         15 . The apparatus of  claim 12 , said composite of molybdenum silicide and silicon nitride comprising a Mo:N ratio of greater than 2:1 and less than 7:1. 
     
     
         16 . The apparatus of  claim 12 , said composite of molybdenum silicide and silicon nitride comprising less than ten percent by weight of elements with an atomic number of less than seven. 
     
     
         17 . The apparatus of  claim 12 , said heating element further comprising a contacting layer substantially contacting said electrically conducting layer, said contacting layer comprising at least one of:
 a silicon nitride layer; and   a silicon oxide layer.   
     
     
         19 . The apparatus of claim  18 , further comprising:
 a pair of electrical insulating layers on opposite sides of said electrically conductive layer.